Bimaxillary jaw expanding appliance

ABSTRACT

A new a telescoping assembly or advancing sheath and a expansion complex are provided for a maxillary or mandibular arch expander. The advancing sheath is provided with a spring which extends between a forward end of the anterior tube and a forward end of the posterior tube. The spring urges the anterior tube rearwardly relative to the posterior tube to compensate for jaw pressure and to help prevent the jaw pressure from threading the anterior tube rearwardly. 
     The expansion complex includes an outer housing and an advancing member which is telescopically received in the outer housing. The two portions of the expansion complex are received in opposed halves of a plate which fits against the mandibular or maxillary arch. An threaded rod and a parallel post extend through the housing. An activation nut is received on the threaded rod, and an activation plate is journaled about both the rod and the post. The activation plate is moved by movement of the activation nut. A spring is journaled about the post between the forward end of the advancing member and the activation plate. The nut is accessible through a channel in the top surface of the housing and advancing member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.09/598,766, filed Jun. 22, 2000, now U.S. Pat. No. 6,402,510, entitledBuccal Tipping-Resistant Mandibular And Maxillary Arch Expander which isa continuation-in-part of application Ser. No. 09/406,426, now U.S. Pat.No. 6,241,517, filed Sep. 27, 1999 which is a continuation-in-part ofapplication Ser. No. 09/143,071, filed Aug. 28, 1998 now U.S. Pat. No.6,036,488, and entitled Pivotal Mounting Boss For Mandibular AndMaxillary Arch Expander And Jaw Repositioner, which, in turn, is acontinuation-in-part of application Ser. No. 09/065,344, filed Apr. 23,1998, now U.S. Pat. No. 5,919,042, and entitled For Mandibular AndMaxillary Arch Expander And Jaw Repositioner, all of which areincorporated herein by reference. The invention is further related tothe inventions shown and described in U.S. Pat. No. 5,645.422 entitledMandibular And Maxillary Arch Expander, and U.S. Pat. No. 5,769,631,entitled Orthodontic Device, both of which are incorporated herein byreference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE INVENTION

This invention relates generally to orthodontic devices and, inparticular, to an improved jaw expander to widen a patient's jaw.

Orthodontists treating children often need to gain space in a child'smouth for unerupted mandibular incisors and to increase intercaninedistance for narrow archforms, as well as to distilize mandibular firstmolars so that a total increase of archlength is available in the lowerdental arch from first molar to first molar. Furthermore, theorthodontist may want to expand the palate correspondingly.

Mandibular and maxillary arch expanders are known in the art to expandand lengthen the mandibular and maxillary archlengths. The use of sucharch expanders help avoid the need for tooth extraction of permanentteeth due to overcrowding. However, such mandibular arch expanders arerather bulky in design, impede tongue mobility, are uncomfortable towear, and interfere with good oral hygiene. The devices must besubstantial in design to resist torquing or leverage mechanics duringchewing.

To facilitate corresponding enlargement of the maxillary and mandibulararches, telescoping mechanisms have been employed which encourageforward repositioning of the lower jaw as the patient closes intoocclusion. Such devices are commonly referred to as Herbst appliances.Current Herbst appliances include a hollow tube and a rod which istelescopically received in the tube. The tube is connected to themaxillary arch expander and the rod is connected to the mandibular archexpander. Generally, the tube and rod are connected to a band orstainless steel crown by a pivoting connection. The pivot generallycomprises a base casing which is soldered or welded to the band or crownand a screw that is inserted through an eye formed on the end of thehollow tube or rod. The screw threadedly engages the base casing andtightened, leaving enough clearance for the eye to pivot about thescrew. Often the orthodontist uses an arch wire connected between thetwo ends of the arch expander. In the past, to accommodate the archwire, the orthodontist or technician first must attach a rectangularwire tube to the band or crown and then attach the base case on top ofthe rectangular tube. This arrangement has a relatively high profilecaused by the stacking of the rectangular tube and base casing alongwith the increased solder mass.

BRIEF SUMMARY OF THE INVENTION

In this application, a new a telescoping assembly or advancing sheathand a expansion complex are provided for a maxillary or mandibular archexpander.

The telescoping assembly or advancing sheath includes a hollow posteriortube, a hollow anterior tube, and a rod extending through the two tubes.The anterior and posterior tubes are threadably connected so that theoverall length of the advancing sheath can be selectively altered. Anattachment is provided at a forward end of the posterior tube topivotally mount the posterior tube to a tooth band. Another attachmentis provided at the back end of the rod to pivotally connect the rod to asecond tooth band. A spring is provided which extends between a forwardend of the anterior tube and a forward end of the posterior tube. Thespring urges the anterior tube rearwardly relative to the posterior tubeto compensate for jaw pressure and to help prevent the jaw pressure fromthreading the anterior tube rearwardly.

In one embodiment, the posterior tube is externally threaded and theanterior tube is internally threaded. In this embodiment, the spring isjournaled about the posterior tube. The posterior tube is provided witha stop forwardly of the end of the anterior tube, and the spring ispositioned between the posterior tube stop and the forward end of theanterior tube. In a second embodiment, the posterior tube is internallythreaded, and the anterior tube is externally threaded. In thisembodiment, the spring is received within the hollow posterior tube andis journaled about the rod.

The expansion complex includes an outer housing and an advancing memberwhich is telescopically received in the outer housing. The two portionsof the expansion complex are received in opposed halves of a plate whichfits against the mandibular or maxillary arch.

The outer housing includes side walls, a top, a bottom, a back, and anopen front. A channel is formed in the housing top and extendsrearwardly from the front of the housing. A threaded rod extendsforwardly from the housing back wall beneath the channel to beaccessible through the channel. At least one post (and preferably twoposts) extend from the housing back wall parallel to the threaded rod.

The advancing member includes side walls, a bottom, a top, and a frontwall. The advancing member is sized and shaped to e slidably received inthe outer housing. A channel is formed in the advancing member top andextends rearwardly from the front wall. The advancing member channel isaligned with the outer housing channel.

To move the advancing member, an activation nut is threadably receivedon the threaded rod. The nut is accessible through the channels andmovable along the threaded rod by rotation of the nut. An activationwing has a first plate slidably received on the threaded rod in front ofthe activation nut and a second plate slidably received on the post. Thefirst and second plates are operatively connected to each other, andmovement of the activation nut moves the first plate, and hence thesecond plate, relative to the housing and the advancing member. A springis journaled about the post between the activation wing second plate andthe advancing member front wall. When the spring is compressed, iteffectively applies a pressure to the arch to force expansion of thearch.

Guides are provided to facilitate movement of the advancing memberrelative to the housing. The grooves of the outer housing and theadvancing member are both defined by sloped walls, and the sloped wallsof the advancing member channel are adjacent the sloped walls of thehousing channel. Additionally, a groove is provided in the bottomsurface of the advancing member and a corresponding rib is formed on theinner surface of the housing bottom. The rib and groove interaction, aswell the interaction of the sloped walls, act as the guides for themovement of the advancing member.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of a mandibular arch expander and maxillaryarch expander which are shown mounted in a mold and connected by atelescoping assembly;

FIG. 1A is a bottom plan view of the maxillary arch expander mounted inthe mold with the telescoping assembly mounted thereto;

FIG. 1B is a top plan view of the mandibular arch expander mounted inthe mold with the telescoping assembly mounted thereto;

FIG. 1C is a top plan view similar to that of FIG. 1B, but with analternative mandibular arch expander;

FIG. 1D is a top plan view of a mandibular molar space closer which canbe used with the telescoping assembly;

FIG. 2 is a side elevational view of the telescoping assembly, partiallyin cross-section;

FIG. 3 is a front plan view of the telescoping assembly;

FIG. 4 is a side elevational view of a rod of the telescoping assembly;

FIG. 5 is a front elevational view of the rod;

FIG. 6 is a side elevational view of a posterior tube of the telescopingassembly;

FIG. 7 is a rear elevational view of the posterior tube;

FIG. 8 is a side elevational view of an anterior tube of the telescopingassembly;

FIG. 9 is a front end elevational view of the anterior tube;

FIG. 10 is a back end elevational view of the anterior tube;

FIG. 11 is an exploded view of a prior art pivotal mounting bossassembly and an orthodontic band with a rectangular tube interposed toaccommodate an arch wire;

FIG. 12 is a perspective view of the prior art pivotal mounting bossassembly of FIG. 11 attached to an orthodontic band with a rectangulartube interposed to accommodate an arch wire;

FIG. 13 is a perspective view of the improved pivotal mounting bossassembly of the present invention attached to an orthodontic band;

FIG. 14 is a top plan view of the improved pivotal mounting bossassembly;

FIG. 15 is a top plan view, partly in cross-section, of an alternativemandibular arch expander using a telescoping assembly;

FIG. 16 is an enlarged cross-sectional view of the telescoping assemblyof FIG. 15;

FIG. 17 is a cross-sectional view of the telescoping assembly of FIG. 16wherein the telescoping assembly is provided with a coiled spring;

FIG. 18 is a cross-sectional view of a telescoping assembly similar toFIG. 2, but adapted to include a coiled spring

FIG. 19 is a side elevational view of an alternative embodiment of a rodof the telescoping assembly;

FIG. 20 is a front elevational view of the rod;

FIG. 21 is a rear elevational view of an alternative embodiment of theposterior tube;

FIG. 22 is a side elevational view of another alternative embodiment ofa rod of the telescoping assembly;

FIG. 23 is a front elevational view of the rod;

FIG. 24 is a rear elevational view of another alternative embodiment ofthe posterior tube;

FIG. 25 is a side elevational view of yet another alternative embodimentof a rod of the telescoping assembly;

FIG. 26 is a front elevational view of the rod;

FIG. 27 is a rear elevational view of yet another alternative embodimentof the posterior tube;

FIG. 28 is a side elevational view of another embodiment of thetelescoping assembly which compensates for jaw pressure which can causethe telescoping assembly to thread backwards;

FIG. 29 is a side elevational view, partly in cross-section, of analternative embodiment of the telescoping assembly of FIG. 28;

FIG. 30 is a plan view of a further embodiment of a mandibular archexpander encased in plastic and mounted in a patient's mouth;

FIG. 31 is a plan view of the arch expander;

FIG. 32 is a cross-sectional view of the arch expander taken along line32—32 of FIG. 31; and

FIG. 33 is a cross-sectional view of the arch expander taken along line33—33 of FIG. 32.

Corresponding reference numerals will be used throughout the severalfigures of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description illustrates the invention by way ofexample and not by way of limitation. This description will clearlyenable one skilled in the art to make and use the invention, anddescribes adaptations, and variations of the invention, including what Ipresently believe is the best mode of carrying out the invention.

Turning initially to FIGS. 1-1B, an orthodontic appliance 1 of thepresent invention is shown mounted in a mold M of a mouth. Although theappliance 1 is shown mounted in a mold, it will be appreciated that itis designed for use in a human mouth to increase the size of a child'smouth so that the child's permanent teeth will not be crowded when theyerupt. This will reduce the need for extractions of permanent teeth. Theappliance 1 includes a mandibular arch expander 3, a maxillary archexpander 5, and a pair of telescoping assemblies 7 which extend betweenand connect the mandibular and maxillary arch expanders 3 and 5, asdescribed below.

The mandibular and maxillary arch expanders 3 and 5 are substantiallythe same as the arch expanders set forth in my above noted U.S. Pat. No.5,645,422, which is incorporated herein by reference. The mandibulararch expander 3 (FIG. 1B) has a pair of spaced apart forward orthodonticbands 13 which are adapted to attach to the mandibular first primarymolars. Bands 13 each have a boss 15 positioned on the lingual side ofthe bands and a boss 17 positioned on the buccal side of the bands. Thebuccal bosses 17 are adapted to receive screws 19 to connect thetelescoping assemblies 7 to the mandibular arch expander 3, as will bediscussed below. The respective bosses 15 and 17 are integrally formedon the respective bands to provide a substantial metallic body for theattachment of other elements to be described hereinafter.

The bands 13 are interconnected by an expansion complex 21. Theexpansion complex 21 has a pair of metal blocks 23. The blocks 23 eachhave three bores 25, 26, and 27 formed laterally therethrough. The bores25, 26, and 27 of the two blocks 23 are in substantial horizontalalignment. Aligning pins 29 extend through the outer bores 25 and 27.The respective aligning pins 29 are slightly undersized relative to therespective bores 25 and 27 so that the blocks 23 will slide relative tothe pins 29. The middle bores 26 are threaded and receive a threadedscrew 33. There is at least one hole 35 formed through the middle ofscrew 33 between the oppositely threaded ends. The hole 35 accommodatesthe insertion of a small tool to turn screw 33. It will be appreciatedthat threaded screw 33 has oppositely threaded ends. Therefore, whenscrew 33 is rotated in one direction, the blocks 23 are moved away fromeach other and when screw 33 is rotated in the opposite direction, theblocks 23 are drawn toward each other. The blocks 23 slide on thealigning pins 29 and the aligning pins serve to stabilize the expansionscrew complex.

The blocks 23 are mounted to the lingual bosses 15 by curved arms 35which extend between the bosses 15 and the block 23. The curved arms 35can be of any appropriate length and curvature to suitably engage thepatient's teeth. The mold M is made following conventional proceduresand the arms 35 are fabricated to be the appropriate length andcurvature. The arms 35 then are soldered to the appropriate boss 15 andto the expansion screw complex 21.

A rod 37 extends rearwardly from each of the lingual bosses 15. The rod37 can be a small hollow tube, to reduce weight, or can be a solid rod.A stated above, the exact position on the respective bosses 15 where therods 37 are attached and the angle at which the rod 37 extends from thebosses 15 depends upon the patient and the patient's needs. It will beappreciated that arms 35 and rods 37 can be one integral pieceappropriately bent to form the arm and the rod, or the arm and rod canbe separate pieces.

The mandibular arch expander 3 also has a pair of spaced apart rearorthodontic bands 41. The bands 41 generally are molar bands and, inuse, are attached to the permanent first molars. Each band 41 has anintegral boss 43 positioned on the lingual side of the bands. A hollowtube 45 extends forwardly from each boss 43. The hollow tubes 45 have aninternal bore sized to accommodate the sliding insertion of the rods 37,as will be explained in detail below.

A pair of short wires 47 extend perpendicularly from the tubes 45. Therespective short wires 47 extend buccally and serve as occlusal restsand are soldered on the respective tubes at a position corresponding tothe lingual occlusal groove of the deciduous second molars bilaterallyto provide extra support and stability to the tubes.

The forward pair of orthodontic bands 13 are connected to the rear pairof orthodontic bands 41 to promote molar distalization and addedarchlength development by a pair of spring-loaded rod and tubeassemblies. Rods 37 are slidingly engaged in tubes 45. Coil springs 49are positioned around rod 37 and fixed between bosses 15 and the end ofthe tube 45. The coil springs 49 are sized so they abut the ends of thetubes 45 and do not slide over the tubes 45. The respective coil springs49, therefore, urge the forward bands 13 away from the rear bands 41 toincrease palate length.

The coil springs 49 have a preset tension. The preset tension of thespring is selected by the orthodontist to effect the appropriate mesialdistal archlength development in the bicuspid area.

An alternative embodiment of the mandibular arch expander 3′ of thepresent invention is shown in FIG. 1C. The mandibular arch expander 3′is substantially identical to the mandibular arch expander 3 shown inFIG. 1B. It varies, however, in the construction of the expansioncomplex 21′. The arch expander 3′ includes spaced apart forwardorthodontic bands 13′ having lingual bosses 15′. The expansion complex21′ includes a hollow tube 61 extending from one boss 15′ and a rod 63extending from the other boss 15′. The angles at which the tube 61 androd 63 extend from the respective bosses depends upon the shape of thepatient's mouth. The rod 63 is slidingly engaged in the tube 61. A coilspring 65 is journaled around the rod 63 and fixed between the boss 15′and the end of the tube 61. The spring 65 is sized to engage the end ofthe tube 61 and not slip over the tube 61. Therefore, the spring 65urges the forward bands 13′ away from each other. The spring 65 has apredetermined force to be delivered between the molars to widen theanterior canine width.

The maxillary palatal expander 5 (FIG. 1A) has a pair of spaced apartforward orthodontic bands 71 which are adapted to attach to themaxillary molars. The each band 71 has a boss 73 positioned on thelingual side of the bands. The respective bosses are integrally formedon the respective bands. There is an integral curved member or hook 75extending inwardly or lingually from the bosses 73.

A pair of spaced apart rear orthodontic bands 77 are positionedrearwardly of the forward bands 71. The bands 77 each have an integrallingual boss 79 and an integral buccal boss 81. The lingual bosses 79have an integral curved member or hook 83. The buccal bosses 81 eachhave a screw hole to revive a screw 85 to connect the telescoping tubeassemblies 7 to the maxillary arch expander 5.

The forward orthodontic bands 71 are connected to the rear orthodonticbands 77 by a rod 87. Furthermore, the hooks 75 and 83 are embedded inplastic plates 89 and 90. The respective plastic plates are molded tofit the patient's palate. Each plate, with the associated forward andrearward bands, comprises half of the expander 5. The halves of theexpander 5 are biased away from each other to widen the maxillary arch.There is a substantially U-shaped rod 91 imbedded in plate 90. The rod91 has legs which extend out from, and at substantially right angles to,the plastic plate 90. Coil springs 96 and 97 are journaled around thelegs of the rod, respectively. A pair of short tubes 99 are embedded inthe plate 89. The tubes 99 extend out of the palate plate 89 atsubstantially right angles to the palate plate. The tubes 99 are oncomplementary alignment with the legs of the U-shaped rod 91 and areslightly oversized so that the legs can slide into the tubes. Thesprings 96 and 97 abut the ends of the tubes 99 and exert tension forceto urge the halves of the appliance apart. The appropriate tension canbe exerted by selecting springs with the appropriate tension. Themandibular expander 3 of FIG. 1B can be modified to replace itsexpansion complex 21 with the plates 89 and 90 of FIG. A, and to includethe structure associated with the plates 89 and 90.

To facilitate transverse development of the lower jaw relative to theupper jaw, the maxillary and mandibular arch expanders areinterconnected by the telescoping Herbst-type assemblies 7, which areshown in detail in FIGS. 2-10. The two assemblies are identical andinclude a posterior tube 101, an anterior tube 103, and a rod 105 whichextends through the two tubes 101 and 103. The posterior tube 101includes a hollow body 107 which is open at both its front and backends. The body 107 has an outer diameter which is substantially constantbetween its front and back ends. The back end 109 is externallythreaded, as at 111. An arm 113 extends upwardly from the tube's body107 at the front 115 of the body. The arm 113 has an eyelet 117 at itsfree end, the eyelet having a hole 119 therein. Intermediate its frontand back ends, the posterior tube 101 includes a plurality of tick marks121 which are used to indicate the amount of advancement of the anteriortube 103 over the posterior tube 101, as will be described below. Thetick marks 121 are preferably separated by about one-millimeter.

The anterior tube 103 includes a hollow body 123 defining a bore 125therethrough. The tube 103 is open at both its back and front ends 127and 129, respectively. The front end 127 of the tube tapers inwardly, asat 131 such that the very front of the tube 103 has a smaller outerdiameter than the rest of the tube's body 123. As seen in FIGS. 8 and10, the body 123 also tapers slightly from the back of the surface 131to the back 129 of the body 123. The tube 123 is internally threaded atits front end, as at 133. The diameter of the bore 125 is slightlygreater than the outer diameter of the anterior tube 101, and thethreads 111 and 133 of the tubes 101 and 103, respectively, are machinedor otherwise formed so that they will mate. Thus, the anterior andposterior tubes 101 and 103 are threadedly connected together. Notchesor holes 135 are formed on the exterior of the posterior tube body 123.The notches 125 are adapted to receive a tool having a correspondinglyshaped head. The tool can be used to rotate the posterior tube 103relative to the anterior tube 101 when the appliance 1 is mounted in apatient's mouth.

The rod 105 is a generally straight rod. It has a generally constantdiameter slightly greater than the inner diameter of the anterior tube101, so that it may slide relative to the tube 101. At its back end, therod 105 has an eyelet 141 having a hole 143.

The telescoping tube assemblies 7 are assembled by threadedly connectingthe anterior and posterior tubes 101 and 103, and sliding the rod 105into the tube assembly. The rod 105 is slid into the tube assembly suchthat its eyelet 141 will be at the opposite end of the assembly from theanterior tube eyelet 117.

As best seen in FIG. 1, the tube assemblies 7 extend between the forwardbands 13 on the mandibular arch expander 3 and the rear bands 77 on themaxillary arch expander 5. The screws 85 of the maxillary arch expanderpass through the eyelet's 117 of the anterior tubes 101 to pivotallyconnect the tube assembly to the maxillary arch expander. Similarly, thescrews 19 of the mandibular arch expander 3 pass through the eyelets 141of the rod 105 to connect the assembly 7 to the mandibular arch expander3.

When initially inserted in a patient's mouth, the telescoping tubeassemblies 7 are sized such that the back end 129 of the posterior tube103 is in contact with the eyelet 141 of the rod 105 when the patient'smouth is shut. This will apply a forwardly directed pressure on themandible. Thus, with all the components (i.e., the mandibular andmaxillary arch expanders 3 and 5, and the telescoping tube assemblies 7and 8) installed in a patient's mount, the appliance 1 will allow fortransverse development, archlength development, palatal expansion andmandibular advancement, simultaneously without requiring patientcompliance.

By rotating the tube 103 in one direction, the tube 103 will advanceover the tube 101, to shorten the overall length of the tube assembly 7.Conversely, by rotating the tube 103 in a second direction, the tube 103will be retracted relative to the anterior tube, to increase the overalllength of the tube assembly. The extent of the movement of the tubes 101and 103 relative to each other is measured by the tick marks 121. Theinterior threads 33 of the tube 103 and the tick marks 121 of the tube101 are positioned on their respective tubes, such that when the tube101 is threaded into the tube 103, the tick marks 121 will be exposed.By rotating the two tubes relative to each other, the number of tickmarks exposed increases or decreases, depending on the direction ofrotation, to indicate how far the tube assembly has been lengthened orshortened by the rotation of the tubes relative to each other. Thus, byreading the number of tick marks exposed, the practitioner can determinethe amount of advancement that has occurred, as well as the overalllength of the assembly 7.

A mandibular molar space closer 201 is shown in FIG. 1D. As can be seen,it is similar to the mandibular arch expander of FIG. 1C. The molarspace closer 201 has a pair of spaced apart forward orthodontic bands213 which are adapted to attach to the mandibular first primary molars.The bands 213 each have a boss 215 positioned on the lingual side of thebands and a boss 217 positioned on the buccal side of the bands. Thebuccal bosses 217 are adapted to receive screws 219 to connect thetelescoping assemblies 7 to the mandibular arch expander 3. Therespective bosses 215 and 217 are integrally formed on the respectivebands to provide a substantial metallic body for the attachment of otherelements to be described hereinafter. A hook 218 extends from the buccalboss 217 and points forwardly, toward the front of the patients mouth.

The bands 213 are interconnected by an expansion complex 221. Theexpansion complex 221 which is identical to the expansion complex 21′ ofthe mandibular arch expander 3′.

A rod 237 extends rearwardly from each of the lingual bosses 217. Therod 237 can be a small hollow tube, to reduce weight, or can be a solidrod. A stated above, the exact position on the respective bosses 217where the rods 237 are attached and the angle at which the rod 237extends from the bosses 217 depends upon the patient and the patient'sneeds.

The mandibular molar space closer 201 also has a pair of spaced apartrear orthodontic bands 241. The bands 241 generally are molar bands and,in use, are attached to the permanent first molars. Each band 241 has anintegral boss 243 positioned on the lingual side of the bands. A hollowtube 245 extends along the lingual side of the band and through the boss243. The hollow tubes 245 have an internal bore sized to accommodate thesliding insertion of the rods 237. The rods 237 sized such that theywill pass through the tubes 245 to extend beyond the rear of the tubes245.

The forward pair of orthodontic bands 213 are connected to the rear pairof orthodontic bands 241 to reduce the spacing between molars using apair of spring-loaded rod and tube assemblies. Rods 237 are slidinglyengaged in tubes 245, as noted. Coil springs 249 are connected to therod 237 behind the rear molar band 241 and to the hooks 217. As seen, inthis position, the springs 249 are in an expanded state. The respectivecoil springs 249, therefore, pull the bands 213 and 241 towards eachother to decrease the spacing between molars. The coil springs 249 havea preset tension. The preset tension of the spring is selected by theorthodontist to effect the appropriate mesial distal archlengthdevelopment in the bicuspid area.

A prior art mounting boss assembly gerry-rigged to accommodate an archwire W is shown in detail in FIGS. 11 and 12 and indicated generally byreference numeral 275 shown in use with an orthodontic band 276. It willbe appreciated that assembly 275 is described as attached to anorthodontic band but can be attached to a stainless steel crown as wellAssembly 275 functions as the above described bosses attached to theorthodontic bands. However, assembly 275 is modified to allow theattachment of arch wires. The prior art assembly 275 includes a shortsegment of square tubing 277 which is attached to the band 276 bysoldering, as at S1, for example. The square tubing is positioned on theorthodontic band for the attachment of an arch wire W, if needed. Amounting boss 278 including a base casing 280 and a screw 282 is thensoldered on top of the square tubing. It will be appreciated by thoseskilled in the art that the prior art assembly 275 requires asubstantial solder joint S1 to secure the elements which results in ahigh profile boss. Moreover, installation of the boss on the bandrequires addition time and costs.

An improved pivotal mounting boss is illustrated in FIG. 13 and shown inapplication in FIGS. 1, 1C and 2 is indicated generally by referencenumeral 300. Mounting boss 300 includes a base casing 302 and a threadedscrew 304. Base casing 302 includes a generally cylindrical base segment305 and a concentric cylindrical body segment 306. Base segment 305 hasan opening 308 formed therein. In the illustrated embodiment opening 308is rectangular and is designed to accommodate a conventional arch wireW. See FIG. 14. The base segment 304 can be positioned on theorthodontic band 276 and soldered in place with solder S2. It will beappreciated that the opening 308 can be positioned at a predeterminedangle as desired by the orthodontist for root angulation. It will beappreciated that less solder S2 is required to attach the mounting boss300 to the orthodontic band resulting in less bulk and a lower profilearrangement than that shown in FIG. 12.

The body segment 306 includes an internally threaded bore 310 for thethreaded engagement of screw 304 The screw 304 is inserted through theeyelet of the orthodontic device described above and tightened, leavingenough clearance so that the eyelet can rotate or pivot about the screw.

Another mandibular arch expander 401 is shown in FIG. 15. Although theexpander 401 is shown embodied in a mandibular arch expander. It will beapparent that it can also be embodied in a maxillary arch expander. Theexpander 401 is substantially similar to the expander 3 of FIG. 1B. Themandibular arch expander 401 has a pair of spaced apart forwardorthodontic bands 413 which are adapted to attach to the mandibularfirst primary molars. The bands 413 each have a boss 415 positioned onthe lingual side of the bands and a boss 417 positioned on the buccalside of the bands. The buccal bosses 417 are adapted to receive screws419 to connect the telescoping assemblies to the mandibular archexpander.

A rod 437 extends rearwardly from each of the lingual bosses 415. Therod 437 can be a small hollow tube, to reduce weight, or can be a solidrod. A stated above, the exact position on the respective bosses 415where the rods 437 are attached and the angle at which the rod 437extends from the bosses 415 depends upon the patient and the patient'sneeds.

The mandibular arch expander 401 also has a pair of spaced apart rearorthodontic bands 421. The bands 421 generally are molar bands and, inuse, are attached to the permanent first molars. Each band 421 has anintegral boss 423 positioned on the lingual side of the bands. A hollowtube 425 extends forwardly from each boss 423. The hollow tubes 425 havean internal bore sized to accommodate the sliding insertion of rods 437which extend rearwardly from the forward orthodontic bands 413. Springs429 are mounted on the rods 427 to apply a pressure to the forwardorthodontic band, as discussed above. It will be appreciated that arms429 and rods 437 can be one integral piece appropriately bent to formthe arm and the rod, or the arm and rod can be separate pieces.

The difference between the mandibular arch expanders 3 and 401 lie inthe expansion complexes of the two expanders. The expansion complex 441uses an advancing sheath design which is similar to the sliding element7 of FIGS. 2-10. The expander assembly is shown on an enlarged scale inFIG. 16. It includes a body 443 and a rod 445. The body 443 is hollowand defines a passageway 447 through the body. The passageway is open atits back end 449 and its front end 451. The body 403 is internallythreaded, as at 452. The threads 453 are shown to be spaced rearwardlyof the front end 451 of the passageway 447. However, the threads canextend throughout as much or as little of the body passageway asdesired.

An arm 453 is received in the back end 449 of the passageway 447 andextends through the body 443 and out the front end 451 of the body 443.The arm 453 extends from the lingual boss 415 of one of the forwardmolar bands 413. The arm 453 and body boss 447 are sized so that thebody 443 can rotate about the arm 453.

The rod 445 is sized to fit within the body passageway 447. A rearportion 461 of the rod 445 is externally threaded, so that the rod canbe screwed into the body 403. At least a portion of the rod 445 ishollow, defining a bore 462 which extends forwardly from the back end ofthe rod 445. The bore 462 is sized to telescopically receive the forwardend of the arm 453. A plurality of tick marks 463 are formed on the rod445 forwardly of the threads. As with the assembly 7, the tick marks 463enable the practitioner to know how far the rod 445 is extending fromthe body 403. The forward end 465 of the rod 445 is soldered, orotherwise fixed to, the lingual side of the other forward orthodonticband 413.

Thus, the rod 445 is effectively fixed to one of the forward orthodonticbands and the body 443 is effectively rotationally mounted to the otherof the forward orthodontic bands. As seen in FIG. 15, the back end 449of the body 443 is in abutting contact with the band 413 to which thearm 453 is mounted. Therefore, by rotating the body 443 relative to therod 445, the overall length of the expansion complex can be selectivelyincreased over time to increase the width of a patients jaw. Using thetick marks 463 on the rod 445, the dentist or technician can determinethe overall length of the expansion complex, and can thus monitor thepatient's progress.

A modified expansion complex 401′ is shown in FIG. 17. The expansioncomplex 401′ is substantially identical to the expansion complex 401 ofFIG. 15, and includes the rod 445 and arm 453. The difference is thatthe passage 447′ of the body 443′ is counterbored, as at 447A, toeffectively produce a passage of two different diameters, the passagehaving a larger diameter in the back portion 447A than in the frontportion 447B, with a shoulder 446 at the transition between the twosections. A coiled spring 448 is received in the counterbored portion447A of the passage 447′ and is coiled about the arm 453. The spring 448is preferably a nickel-titanium spring and is sandwiched between themolar band 413 to which the arm 453 is mounted and the shoulder 446. Theadvantage of the spring 448 is that it will apply a constant pressure tothe mandible to expand the mandible. Further, the expansion force comesfrom the spring, rather than from the back edge of the body 443.However, adjustments would still be made by rotating the body 443. Thepassage 447 in the body 443 (FIGS. 15 and 16) need not extend all theway through the body 443. The body could have a rear bore which acceptsthe arm 453 and a forward internally threaded bore which excepts the rod445. This example is merely illustrative.

FIG. 18 shows a telescoping assembly 507 similar to the assembly 7 ifFIG. 2. However, the assembly 507 has been modified to include a spring548 in the body 503, similarly to the telescoping assembly 441 of FIG.17.

Although the foregoing designs work well in most treatments, theinventor has determined that there can be some molar crown tipping inthe transverse dimension analysis. To correct that problem, the inventorhas developed modifications to the design that feature tubes havingcylindrical outer configuration with an inner lumen that has flat sides.The rod which seats in the lumen has a complementary configuration. Thisdesign resists the turning or rotation of the rod within the tube whichcan result in molar crown tipping during treatment. The new designs arebest illustrated in FIGS. 19-27.

FIGS. 19-21 illustrate one embodiment of the modified tube and rodindicated by reference numerals 600 and 601 respectively. As will beappreciated, the gross structure of the modified tube and rod aresimilar to those described above. However, as best seen in FIGS. 20 and21, the rod 600 has a rectangular cross section. Tube 601 has acomplementary rectangular bore 603, which is slightly oversized relativeto tube 601 to allow the introduction of rod 600 into bore 603. As willbe appreciated, the rectangular shapes of the bore and rod prevent therod from turning or rotating within the tube to retard molar tipping inuse.

FIGS. 22-24 illustrate another embodiment of a modified tube and rodindicated by reference numerals 700 and 701 respectively. As will beappreciated, the gross structure of the modified tube and rod aresimilar to those described above. However, as best seen in FIGS. 23 and24, the rod 700 has an ovoid cross section. Tube 701 has a complementaryovoid bore 703, which is slightly oversized relative to tube 701 toallow the introduction of rod 700 into bore 703. As will be appreciated,the ovoid shapes of the bore and rod also prevent the rod from turningor rotating within the tube to retard molar tipping in use.

FIGS. 25-27 illustrate another embodiment of the modified tube and rodindicated by reference numerals 800 and 801 respectively. As best seenin FIGS. 26 and 27, the rod 800 has a substantially rectangular crosssection with rounded top and bottom outer walls 802A and 802B,respectively. Tube 801 has a complementary substantially rectangularbore 803, having an arced or rounded top wall 804A and rounded bottomwall 804B which is slightly oversized relative to tube 601 to allow theintroduction of rod 800 into bore 803. The rounded walls on the tube androd facilitate ease of movement for adjustment; the flat side wallsfacilitate soldering and prevent the rod from turning or rotating withinthe tube to retard molar tipping.

The designs shown in FIGS. 22-27 can be employed in any of thepreviously described and illustrated expanders. The designs of FIGS.22-27 can be used to replace rod 37 and tube 45 as shown in FIG. 1B.Likewise the embodiments of FIGS. 22-27 can be incorporated in theexpander shown in FIG. 1D in place of rod 237 and tube 245. The presentinvention contemplates the use of a rod and tube assembly that resiststwisting or rotation in any expander that uses a novel rod and tubeassembly. It will be appreciated that the illustrated designs thatresist twisting or rotation are intended to be usable in any orthodonticexpander that includes at least one rod and tube assembly.

The inventor has also found that with respect to the advancing sheath,the jaw pressure to return to a retruded chin position may cause theadjustable tube of the advancing sheath to thread backwards after it hasbeen advanced. A modified advancing sheath is shown in FIG. 28. Theadvancing sheath 801 includes a hollow posterior tube 803, a hollowanterior tube 805, and a rod 807 which extends through the two tubes 803and 805. The posterior tube 803 is externally threaded at its back end.The anterior tube 805 is internally threaded to be threaded onto theback end of the posterior tube to facilitate adjustment of the overalllength of the sheath through which the rod 807 extends. An arm 809extends upwardly from the posterior tube's forward end. An attachment811 is formed at the free end of the arm to connect the tube to a toothband. A second attachment 810 is formed on the back end of the rod 807.A spring 812, preferably a coil spring made from a nickel titanium, isjournaled about the posterior tube 803 between the forward end 813 ofthe anterior tube 805 and the arm 809 of the posterior tube 803. A stop815 is provided just behind the arm 809 to form a forward stop for thespring 812. The spring 812 will place a constant forward pressure on theadvancing or posterior tube 805 to assist it in resisting the tendencyfor the tube 805 to back up under constant retrusive jaw pressure.

A variation of the advancing sheath 801 is shown in FIG. 29. In theadvancing sheath 801′, the posterior tube 803′ is internally threadedand the anterior tube 805′ is externally threaded. In this variation,the spring 812′ is received within the tube 803′ between a forward end815′ in the tube 803′ and a forward end 813′ of the anterior tube 805′.

In FIGS. 30-33, an alternative expansion mechanism 900 is shown. In FIG.30, the location of the expansion member 900 is shown embedded withinthe halves 902A and 902B, of the expansion mechanism or plate 902. InFIGS. 32-33, the specific construction of the type of expansionmechanism 900 to be used, in the manner as shown in FIG. 30, is moreaccurately disclosed, and described here and after. The expansionmechanism 900 is encased in a plate 902 having halves 902 a and 902 bwhich are sized and shaped to fit against a patient's mandibular ormaxillary arch. The expansion mechanism 900 includes an outer housing910 having side walls 912, a top 914, a bottom 916, a back 917, and anopen front 918. A channel or groove 920 extends rearwardly from thefront edge 918 of the outer housing 910. The groove 920 is defined bysloped walls 922 on opposing sides of the channel. Thus, as seen in FIG.32, the bottom of the sloped wall 922 is below the inner surface of therest of the top 914. A triangular shaped rib 924 runs along the centerof the inner surface of the bottom 916 between the back 917 and thefront 918. A threaded rod 926 extends forwardly from the housing backwall 917 to the front 918. The threaded rod 926 extends along the centerof the housing, and is generally above the rib 926. A pair of posts 928are disposed on opposite sides of the threaded rod 926, and, like therod 926, extend forwardly from the back wall 917 to the front wall 918.

An advancing member 930 is slidably received in the housing 910. Themember 930 has side walls 932, a bottom 934, a top 936, and a front wall937. A forward mounting portion 939 extends from the front wall 937. Agroove 938 is formed on the outer surface of the bottom 934 and is sizedand shaped to slide on the rib 924 of the housing 910. Additionally, achannel 940 having sloped walls 942 is formed in the top 936. Thechannel 940 is aligned with the housing channel 920, and the slopedwalls 942 are complimentarily shaped to the housing's sloped walls 922.Thus, the interaction of the groove 938 with the rib 924 and of thesloped walls 922 and 942 surrounding the channels 920 and 940,respectively, act as keys or guides for the member 930 as it is moved,as will be discussed below.

An internally threaded activation nut 950 is received on the housing'sthreaded rod 926. The nut 950 is sized such that its peripheral edge isaccessible through the channels 920 and 940. The nut 950 includes aplurality of holes 952 in its periphery. The holes 952 are accessiblethrough the channels 920 and 940 using a tool to rotate the nut 950. Ascan be appreciated, by rotating the nut 950, the nut 950 will move alongthe rod 926.

An activation wing 960 is mounted in the housing 910 in front of theactivation nut 950 to be moved by the nut. The wing 960 includes acentral portion 962 which is journaled about the threaded rod 926. Thecentral portion 962 has a central opening sized to prevent the threadsof the rod 926 from interfering with movement of the activation wing960. A pair of arms 964 extend from opposite sides of the centralportion 962, and a plate 966 is on the distal end of each arm 964. Theplates 966 each have a central hole sized to be received on the posts928. A spring 968 is journaled around each post 928 between the plates966 and the front wall 937 of the movable member 930.

As can be appreciated, by rotating the nut 950 such that it moves towardthe movable member front wall 937, the activation wing 960 will be movedforwardly, and the springs 968 will be compressed. The springs 968 willthus apply a pressure against the moveable member 930 to cause thehousing 910 and the moveable member 930 to move relative to each other,thereby causing expansion of the member 900. Preferably, the moveablemember 930 is provided with markings 970, such as millimeter markings sothat it can be determined how far the moveable member 930 has beenadvanced. The markings 970 are preferably provided on the mountingportion 939 of the advancing member 930. When the expansion complex 900is fixed in the plates 902 a and b, the housing 910 is fixed in one ofthe plates, such as plate 902 a, and the advancing member 930 is mountedin the other of the plates, such as plate 902 b. The housing 910 can beeffectively seated in an appropriately sized and shaped opening in theplate 902 a. The advancing member 930 is mounted to the plate 902 busing the mounting portion 939. The mounting portion 939 is received ina groove or opening at an inner edge of the plate 902 b. When the twohalves of the expansion complex are fixed in their respective platehalves, the channels 920 and 940 will be accessible, and the markings970 will be visible. The outer surfaces of the housing 910 and theadvancing member 930 which are fixed to the plates 902 a,b, can haveroughened surfaces to facilitate permanent attachment of the housing 910and advancing member 930 to their respective plates 902 a,b.

In view of the above, it will be seen that the several objects andadvantages of the present invention have been achieved and otheradvantageous results have been obtained. Furthermore, since variouschanges and modifications may be made in the assemblies of the presentinvention without departing from the scope of the claims, the foregoingdescription and accompanying drawings are intended to be illustrativeonly and should not be construed in a limiting sense. For example,although the rib 924 and groove 938 are shown to be triangular, the riband groove could be any other desired shape. More than one rib andgroove could be provided. Additionally, the rib and groove could bereversed, such that the rib is on the advancing member 930 and thegroove is on the housing 910.

What is claimed is:
 1. A telescoping assembly for a mandibular ormaxillary arch expander; the telescoping assembly including: a hollowposterior tube, the posterior tube being threaded at least at a back endthereof and having an attachment at a forward end thereof, theattachment being mountable to a tooth band; a hollow anterior tube, theanterior tube being threaded at a forward end thereof to be threadedly,and adjustably, mounted to the posterior tube; a rod which extendsthrough the anterior and posterior tubes, the rod having an attachmentat a back end thereof the attachment being mountable to a tooth band;and a spring extending between a forward end of said anterior tube and aforward end of said posterior tube, said spring urging said anteriortube rearwardly relative to said posterior tube to compensate for jawpressure.
 2. The telescoping assembly of claim 1 wherein the spring ismade from a nickel titanium.
 3. The telescoping assembly of claim 1wherein the posterior tube is externally threaded and the anterior tubeis internally threaded.
 4. The telescoping assembly of claim 3 thespring is journaled about the posterior tube.
 5. The telescopingassembly of claim 4 wherein the posterior tube includes a stop forwardlyof the end of the anterior tube, the spring being positioned between theposterior tube stop and the forward end of the anterior tube.
 6. Thetelescoping assembly of claim 1 wherein the posterior tube is internallythreaded, and the anterior tube is externally threaded.
 7. Thetelescoping assembly of claim 6 wherein the spring is received withinthe hollow posterior tube and is journaled about the rod.
 8. Anexpansion complex for a mandibular or maxillary arch expander, theexpansion complex including: an outer housing; the outer housingincluding side walls, a top, a bottom, a back, and an open front; achannel in the housing top extending rearwardly from the front of thehousing; a threaded rod extending forwardly from the housing back walland being accessible through the channel; and at least one postextending parallel to the threaded rod; a advancing membertelescopically received in the housing; the including side walls, abottom, a top, and a front wall; a channel in the top and extendingrearwardly from the front wall, the advancing member channel beingaligned with the outer housing channel; an activation nut threadablyreceived on said threaded rod, said nut being accessible through saidchannels and movable along said threaded rod by rotation of said nut; anactivation wing including a first plate slidably received on saidthreaded rod and a second plate slidably received on said post, saidfirst and second plates being operatively connected to each other; saidfirst plate being positioned adjacent said activation nut; said firstplate, and hence said second plate, being movable relative to saidhousing and said advancing member by rotation of said activation nut;and a spring journaled about said post between said activation wingsecond plate and said advancing member front wall.
 9. The expansioncomplex of claim 8 wherein the grooves of the outer housing and theadvancing member are both defined by sloped walls; the sloped walls ofthe advancing member channel being adjacent the sloped walls of thehousing channel.
 10. The expansion complex of claim 8 wherein a grooveis formed on one of the inner surface of the housing bottom and theouter surface of the advancing member bottom, and a rib is formed on theother of the inner surface of the housing bottom and the outer surfaceof the advancing member bottom; the rib and groove being complimentarilyshaped and positioned such that the rib is received in the groove. 11.The expansion complex of claim 8 wherein the advancing member includesmounting portion extending from the front wall.
 12. The expansioncomplex of claim 8 wherein the activation nut includes a plurality ofholes in its periphery; the holes being accessible through the channels13. The expansion complex of claim 8 including indicia on one of saidouter housing and advancing member to gauge the amount of expansion ofthe expansion member.
 14. An arch expander for a mandibular or maxillaryarch, the arch expander including: an plate positionable against one ofsaid mandibular and maxillary arch; said plate including a first halfand a second half; an expansion complex in said plate, said expansioncomplex including a housing fixed in said first plate half and anadvancing member telescopically received in said housing and fixed insaid second plate half; and an advancing sheath having a first end and asecond end, said first end being pivotally connected to a first toothband and said second end being pivotally connected to a second toothband; the advancing sheath having: a hollow posterior tube having afirst end and a second end; said posterior tube first end being saidadvancing sheath first end; the posterior tube being threaded at leastat a back end thereof and having an attachment at a forward end thereof,the attachment being mountable to said first tooth band; a hollowanterior tube, the anterior tube being threaded at a forward end thereofto be threadedly, and adjustably, mounted to the posterior tube; a rodwhich extends through the anterior and posterior tubes, the rod having afirst end and a second end; said rod second end being said advancingsheath second end; the attachment being mountable to said second toothband; and a spring extending between a forward end of said anterior tubeand a forward end of said posterior tube, said spring urging saidanterior tube rearwardly relative to said posterior tube to compensatefor jaw pressure; the expansion complex including said outer housing andsaid advancing member: the outer housing including side walls, a top, abottom, a back, and an open front; a channel in the housing topextending rearwardly from the front of the housing; a threaded rodextending forwardly from the housing back wall and being accessiblethrough the channel; and at least one post extending parallel to thethreaded rod; the advancing member including side walls, a bottom, atop, and a front wall; a channel in the top and extending rearwardlyfrom the front wall, the advancing member channel being aligned with theouter housing channel; an activation nut threadably received on saidthreaded rod, said nut being accessible through said channels andmovable along said threaded rod by rotation of said nut; an activationwing including a first plate slidably received on said threaded rod anda second plate slidably received on said post, said first and secondplates being operatively connected to each other; said first plate beingpositioned adjacent said activation nut; said first plate, and hencesaid second plate, being movable relative to said housing and saidadvancing member by rotation of said activation nut; and a springjournaled about said post between said activation wing second plate andsaid advancing member front wall.